Dental oral irrigating apparatus presently exists for generating and applying a stream of liquid to areas of a person's mouth. Some such apparatus are electrically powered and present potential danger to the user.
Other such apparatus are powered and controlled by the liquid pressure from a water line. In particular prior U.S. Pat. Nos. to Drapen, 3,225,759 and to Halem, et al., 5,004,158 (embodiment of FIG. 2) disclose dental oral irrigating apparatus powered and controlled by water line pressure and having movable pistons for discharging a secondary or supplemental liquid. These prior art devices do not however disclose a selectively operable valve to selectively couple an inlet port from the water supply to either (1) the outlet orifice of the irrigating apparatus or (2) the face of the piston opposed to the secondary liquid.